There are many inventions which attempt to technically solve the need for having movable surfaces applied to various fields of the art. Some of these inventions are based on the blind concept such that they use a series of slats or elements attached to one another arranged according to a mainly planar surface but which can be wound around a drum such that by means of the rotation of the drum said slats take up a circumferential position around it, the length of the horizontal surface being modified.
An example of application can be seen in U.S. Pat. No. 2,958,083A, where this concept is used for covering a swimming pool. Other patents such as WO9708408A try to solve the mechanism which allows covering or removing covers using this concept or covers of other types.
U.S. Pat. No. 4,341,253A uses an equivalent system for covering a vehicle service pit, and U.S. Pat. No. 1,707,287A uses a similar concept for forming a vertical door serving as protection against fire. U.S. Pat. No. 2,173,900A applies a cover formed by slats for protecting an escalator, said cover not forming part of the machine itself.
There are also inventions describing different solutions for opening walkway and escalator pit covers. For example, patent JP8188365A describes various solutions of systems for opening maintenance pit covers for reducing the effort needed.
In summary, it can be said that there are inventions describing systems for opening pit covers in escalators and also various cover systems by means of blind slats as well as mechanisms for actuating them.
The present invention seeks to apply the blind concept to form a longitudinal joint between two fixed pit covers the relative distance of which will vary due to different reasons and without applying any manually or mechanically operated mechanism and forming a treadable continuous surface for the users of escalators or moving walkways.
In some escalator or moving walkway inventions, a fixed relative position between the overturn position of the steps or pallets and the combs is used, whether it is through the traditional step or pallet chain or when in its place the steps or pallets themselves are attached to one another forming a continuous band. When this occurs in the upper head no special action is required, but given that said step or pallet chain or the band formed by them requires being tensed, its position is modified with respect to the fixed part, therefore if the position of the combs is maintained with respect to the band of steps or pallets it is necessary to have a surface which allows varying the length between said adjacent surfaces.